In a message dated 12/16/98 3:26:01 AM Eastern Standard Time, [log in to unmask]
writes:

>  Salts can rot both the concrete and the rebar.  Dissolved salts in the
>  concrete can crystallize when the water evaporates.  The forces of
>  crystallization can break the concrete matrix.  Salts can also corrode the
>  steel, and corrosion jacking can ensue, or the steel will just dissolve.

For the last five years we have been maintaining a polysulfide sealant joint
in a country club swimming pool located on the North Shore of LI that is close
enough to the beach that the bottom of the pool is below tide level. Though we
have been able to maintain a sealed joint for the length of a summer pool
season, every few years we have to replace the sealant. The last time the
replacement was ahead of the cycle we believe due to a failure of the sealant,
which on occasion happens and usually to everyone's dismay.

Each time the replacement is a perplexing task as we have to maintain a dry
condition at the joint with the pressure of a rising tide.

Whenever the grounds people notice that the water is lowering they send in
divers with pieces of plastic wrap that they let loose to be, I assume, sucked
in where the joint has failed. In some areas the joint blows outward and the
failure is easier to locate.

The one thing that I have been curious about, and that nobody seems to have
been able to answer, is if the salts from the water of LI Sound would have an
effect either on the concrete or on the bond of the sealant?

I believe that the chlorine in the pool, as well as the relatively more stable
water temperature, as compared to air temperature, will also affect the
performance of the joint.

][<en Follett